The Curious Way Kangaroos Stay Cool

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The Australian Outback is one of the hottest places on earth. In the summertime, daytime temperatures hover between 95-105°F. Night time is slightly cooler, but not much, as temperatures average around 77°F. Add stifling humidity, and you get a scorching climate that’s challenging to endure for extended periods.

The Outback is also home to a wide array of animals. Thanks to an eternity in the desert and the evolutionary adaptations borne out of thousands of generations, these animals have developed unique ways to stay safe and cool. Take the kangaroo, for example. It’s the largest member of the marsupial family, calling places like Australia and New Guinea home.

A unique-looking animal, the kangaroo has large hind legs, an equally large stabilizing tail, and a small head. Their habitat is arid and unforgiving, but kangaroos have developed unique methods for staying cool. Their appearance, at first glance, seems almost alien. Their features, however, are perfectly designed for the Outback and all the dangers that come with it. Watch the video above, and then we will explore the topic further.

How Hopping Keeps Them Cool

One well-known characteristic of kangaroos is that they hop from place to place, which is a highly efficient way to travel. They have incredibly strong calf muscles and a large collection of tendons that run from their tails to their hip bones. Their large hind feet function like tightly coiled springs. They save energy by using the recoil of their springy tendons to keep them moving instead of wearing themselves out using their muscles. Combine these elements with a tail that works like a rudder, and you have a recipe for nature’s perpetual motion machine.

All these features allow kangaroos to jump up to 30 feet at a time. They can also change direction in mid-air. When kangaroos get to hopping and reach their average speed of 20 miles per hour, they burn less energy while moving quickly. Simultaneously, this decreased energy expenditure allows these marsupials to keep water drinking at a minimum, which is a risk of predatory attack, while still beating the heat.

Cool Off in the Pouch

When a baby kangaroo, or joey, is born, they are underdeveloped, delicate, and no bigger than a lima bean. After a fairly short gestation period of 31-36 days, joeys arrive with development only in their forearms. This allows them to climb up their mother’s pouch where they stay safe for up to nine months before venturing out more on their own.

Not only do the pouches protect younglings from predators, but they also relieve them from the harsh pressures of the environment. The pouch keeps a joey cool, well-fed, and hidden from eager predators until they are big enough to stand on their own two feet.

Sweating and Panting

Once mature, kangaroos use several fascinating advantages for dealing with the heat. While kangaroos stay active at night and hunker down in the daytime, if they are out during the day in dangerous temperatures, kangaroos will hop to the nearest spot of shade where they may dig out several inches of dirt before laying down on the cooler earth beneath.

Kangaroos also sweat — a body’s natural way of cooling off. But they only sweat while they hop. Once they stop hopping, their sweating ceases and they start panting at an incredible rate. This rhythmic panting can reach up to 300 breaths per minute. It seems severe, but it allows the kangaroo to keep a constant flow of air over their windpipe which keeps them from overheating.

Saliva and Forearms

While all of the above features keep a kangaroo from overheating in the harsh temperatures of the Outback, perhaps the most fascinating way they endure the elements has to do with their forearms. Well-known as boxers, kangaroos use their thick, muscled arms to settle disputes. Lower down the limbs, however, are their forearms, which are thin and bony but provide a serious means of survival in the brutal heat.

When trying to cool down, kangaroos find a spot of cool shade and lick the palm side of their forearms. Thanks to a network of hundreds of blood vessels right under the skin, the saliva on their arms evaporates in the high heat. As the moisture evaporates, it absorbs heat from the skin and lowers the body temperature. This forearm licking can also enhance blood flow from that network of blood vessels to the skin’s surface, which dispels heat quickly. Due to the relatively large surface area of kangaroo forearms, with not much muscle in between, this licking process can cool them down at a moment’s notice.

A Powerful Symbol

Thanks to all these evolutionary advantages, kangaroos have survived the unforgiving Australian Outback for millennia. While humans brought widespread changes to their environment via agriculture and hunting, these animals have adapted to a changing environment and remain relatively plentiful thanks to their ability to roll with the punches and beat the heat.